1. Field of the Invention
The present invention relates to an optical apparatus, and in particular to a compact optical apparatus for use on an object surface with limited area, that offers high accuracy and low assembly cost.
2. Description of the Related Art
Applications relative to optical interface technology, such as optical pointing devices, have become increasingly popular. For example, conventional and optical pointing devices and optical pens are successful applications of apparatuses employing optical sensor technology. As the demand increases for functions, mobility and small size of the optical apparatuses, it becomes a challenge to product such apparatuses with impact size, high accuracy, simple assembling processes and low cost of assembling.
With respect to the conventional optical pointing devices and optical pens, mobility increases with reduced size such that they are more convenient, particularly for use with mobile computers. Moreover, as the conventional optical apparatus generally includes a plurality of internally disposed optical components (lenses, sensor and optical guiding mechanisms), various types of packaging technology can be applied thereto. Generally, the optical components are assembled before being packaged inside the product. As the number of functions and components increase, however, the optical apparatus package inevitably trends toward integration and modulization to save space.
FIG. 1 is a sectional view of a conventional optical pen. As shown in FIG. 1, a conventional optical pen 1 is applied to an object surface 2. The displacement relative to the object surface 2 can be sensed by an optical sensor 6 receiving light reflected by the object surface 2. As shown in FIG. 1, the optical pen 1 has a light emitting diode (LED) 3 emitting light which passes through a light guiding mechanism 4. The light guiding mechanism 4 comprises a first light guiding element 41 and a second light guiding element 42. The arrow in FIG. 1 shows the path of light emitted from the light emitting diode (LED) 3 as it passes through the first and second light guiding elements 41 and 42 sequentially, and is projected on the object surface 2 under a lens 5 such that the reflected light is easily received by the optical sensor 6. Particularly, the sensor 6 is disposed above the lens 5 and is capable of efficiently guiding the reflected light to the sensor 6.
With respect to the conventional mechanism of an optical apparatus as mentioned above, however, the light emitting diode (LED) 3, the light guiding mechanism 4 and the lens 5 are independently installed in the optical pen 1 and occupy a large space due to the components'size. Additionally it is difficult to install the components in the small space provided by the package with a high degree of accuracy and sensitivity.
To address the above mentioned disadvantages, another conventional optical pointing device is shown in FIG. 2. The optical pointing device comprises a frame 11. The frame is a traditional lead-frame type IC package structure, wherein the frame 11 has a plurality of pins 14 connected to an external circuit or a computer. As shown in FIG. 2, an optical sensor chip 12 is fixed in a hollow space 11′ in the frame 11 such that electrical signal can be delivered by the conducting wires 12′ connected to the pins 14.
Furthermore, a light emitting diode (LED) 7 emits light which passes through a light guiding element 8 and is then reflected by an object surface 9 such that the sensor chip 12 receives the reflected light passing through a light guiding lens 10. The reduced size of the sensor and other components such as the light guiding element 8 and the light guiding lens 10 inside the optical pointing device are integrally mounted on the same structure as shown in FIG. 2, the overall size of the optical pointing device can be greatly reduced.
To improve the conventional optical mechanism of the optical apparatus as mentioned above, the present invention provides an impact optical apparatus with smaller size.